The primary end point is complete remission, defined as remission of proteinuria to <500 mg/day with normal renal function. Partial remission, a secondary endpoint, will be defined as reduction in proteinuria by at least 50% and to <2 g/day with stable renal function (i.e. no more than a 20% increase in serum creatinine). Other secondary endpoints will be based on histologic parameters from renal biopsies performed after 1 year of therapy and compared to pre-treatment (baseline) biopsies; these include change in intensity of C3 staining on immunofluorescence, change in percentage of non-affected glomeruli, change in percentage of interstitial fibrosis and tubular atrophy, and changes in electron dense deposits by electron microscopy. No response will be defined as failure to meet criteria for either complete or partial remission, including patients with unremitting proteinuria, progressive chronic kidney disease, or progression to ESRD.